An integrated keyboard and pointing device system allows a computer user to move a screen cursor smoothly in any direction by pushing on an existing key on the keyboard in whatever direction the cursor is desired to go. U.S. Pat. No. 4,680,577 to Straayer, et al. shows an example of a multipurpose cursor control keyswitch for that purpose.
Operation of an integrated multi-function keyboard system, i.e. a system that provides for both pointing and typing operations without requiring a separate pointing device such as a mouse, requires acquiring pointing data from the keyboard. In an integrated system, pointing data preferably is communicated from the keyboard to the host processor using a known, industry standard communications link between the keyboard and the host. What is needed is a way to communicate pointing data to the host, over that standard interface, in a manner transparent to application software.